The frame bears wheels generally positioned such that their axes of rotation are parallel to each other and perpendicular to said reference planes. These wheels, which are discoid-shaped, may more or less superimpose one another, depending on their position with respect to the frame. One of them, arranged to support the time indicator organs, is positioned near the second reference plane. Traditionally, the wheels such as the assortment (comprising the escapement wheel, the pallets and the double roller) as well as the oscillator are mounted directly on the movement, near the first reference plane. After the movement is mounted, these elements must undergo the usual adjustments, which then require manipulations of the entire movement. These adjustments may prove relatively impractical and delicate.
Furthermore, it is known to use an inclined balance so as to minimize the running variation of a watch. The complexity of the implementation (manufacture and assembly) of the balance and the assortment is then increased.
Another technique consists of mounting the balance in a tourbillon, or a double-tourbillon as for example described in patent CH698 622, but this type of construction is not part of the invention, which relates to “simple” balances whereof the staff is mounted on an element of the frame and not a tourbillon frame.
Furthermore, the incline angle of the balance mounted on the frame is chosen so as to minimize the running variation when worn, i.e., when the watch is used and is either on the wearer's wrist in the case of a bracelet watch or in the wearer's pocket in the case of a pocket watch.
However, the watch is not necessarily always worn, for example at night or when the wearer is using another watch. The duration during which the position of the watch is not modified may cause the running thereof to vary. It therefore appears necessary to minimize the running variation also when the watch is not worn or stays in the same position for a certain amount of time.